234 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
with fleshy structures, which serve to assist its germination and the 
complete absorption of its nutritive tissue. 
Chlorescence of Plants.* * * § — M. E. Belzung refers to the result of 
Palladin’s researches on the chlorescence and growth of etiolated leaves, 
viz., that without sugar, chlorophyll could not develope in a plant, as 
confirming his own view on the relation between the starch-grain and 
the grain of chlorophyll. 
M. Belzung gives the substance of further observations on the forma- 
tion of starch and the use that is made of it. From a fact observed by 
M. Bokorny in Spirogyra majuscula the conclusion is drawn that the for- 
mation of starch is not solely due to the carbon and the elements of 
water, but to the production of various complex organic substances, and 
to the intervention of several other elements, such as nitrogen, potassium, 
&c. 
Effect of Exposure on the relative length and breadth of 
Leaves.!— Hr. G. F. Scott Elliot has made a series of observations on 
variations in the leaf-ratio, i. e. the relation between the length and 
breadth of leaves — produced by various conditions of soil and atmosphere. 
The general result is that exposure (in other words increase of transpira- 
tion) has a tendency to lower the leaf-ratio, that is, to increase the 
breadth of leaves in proportion to their length. A large number of the 
observations were made on tropical grasses, and it was found that in 
them the lowest leaves, which are most protected from wind and sun, 
are proportionately the longest. Similar results were obtained by 
growing the same species in more and in less sheltered situations. 
Experiments on growing the same species in different soils led to no 
very definite results. 
Fixation of Free Nitrogen by Plants. J — MM. T. Schlosing and E. 
Laurent describe certain experiments in which the amount of free 
nitrogen used by various plants is ascertained. There are two methods, 
the direct method and the indirect. The former is without doubt 
superior, and consists in ascertaining the amount of gaseous nitrogen at 
the commencement and at the termination of each experiment. The 
author’s conclusions are : — (1) That certain of the lower green plants 
obtain gaseous nitrogen from the atmosphere. (2) That in the experi- 
ments no measurable amount of nitrogen was fixed by either mustard, 
cress, or spurrey, &c., but peas under the same conditions do absorb 
large amounts of nitrogen from the atmosphere. 
Nitrogen Assimilation of the Leguminosge.§— The objects of the 
experiments on the above subject carried on by Herren F. Nobbe, 
E. Schmid, L. Hiltner, and E. Hotter were (1) to comprise some kinds 
of papilionaceous woody plants, (2) to infect with pure cultivations of 
bacteria from (a) soil and ( b ) root nodules, as well as with soil extracts, 
(3) to ascertain whether one and the 6ame bacterium produces nodules 
in all leguminous plants, or whether the various orders have their 
* Journ. de Bot. (Morot), v. (1891) pp. 350 5. Cf. this Journal, 1891, p. 758. 
t Journ. Linn. Soc. (Bot), xxviii. (1891) pp. 375-85. 
j Comptes Rendus, cxiii. (1891) pp. 776-8. Cf. this Journal, 1891, p. 771. 
§ Landw. Versuclis-Stat., xxxix. pp. 327-59. See Journ. Chem. Soc., 1891, 
Abstracts, p. 1533. Cf. this Journal, 1891, p. 209. 
